There are approximately 80 million people in the US that live in multiunit housing (MUH) where the potential exists for involuntary exposure to SHS from smoking occurring in other parts of their building. The US Surgeon General has reported that there is no safe level of exposure to SHS. Based on our preliminary data, this could be in part due to low levels of knowledge about the dangers of SHS, the lack of understanding the extent to which it transfers between units in MUH, perceived barriers to implementing policies such as lost rental income and the legality of smoke free building policies, and a general apathy among tenants to request a smoke free environment in their building. Using Rogers' Theory of Diffusion as a guiding framework, we aim to conduct a randomized community-based intervention to test whether increases in SHS knowledge, support for smokefree MUH policies, and actual policy implementation can be achieved through an educational intervention that delivers credible scientific information to the appropriate target audiences (i.e., landlords/owners and tenants). The primary hypothesis is that this smokefree MUH educational campaign will increase the fraction of tenants that live in a building that has a 100% smokefree policy at a faster rate than that observed without such an intervention. To test this hypothesis, we propose to conduct a randomized matched-pair community-based intervention trial to measure changes in knowledge about SHS, support for smokefree MUH policies, and actual policy implementation among tenants and landlords/owners. We will work with Americans for Non- smokers' Rights (ANR) to implement the 12 month intervention and to provide technical assistance in 8 pairs of small to mid-sized communities in the US. The intervention will involve the collection and dissemination of scientific survey data obtained at baseline from tenants and landlord/owners as well as air quality data documenting the extent to which SHS transfers between units in a MUH complex. The smokefree MUH educational intervention will be tailored to the specific issues and barriers identified from this baseline data collection. The intervention will be delivered to the target audience (e.g., tenants and landlords/owners) through channels, such as meetings with landlords/owners' and realtors' associations, press conferences, and events to promote smokefree MUH policies. Outcomes examined include changes in knowledge about the dangers of SHS, support for smokefree policies, and the percent of tenants that live in a smokefree MUH.